Control devices for hydraulically ac



April 14. 1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING OR PARKING MECHANISM5 Sheets-Sheet 1 Filed March 23, 1959 deems/11.0 JAM/5s Barman Mm AT-ry.

April 14, 1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING OR PARKING MECHANISM5 Sheets-Sheet 2 Filed March 23, 1959 AkCH/BA L o c/A/V/[S BurrzwmemATT).

April 14, 1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING 0R PARKING MECHANISM5 Sheets-Sheet 5 F/Go.

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Aprll 14, 1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING OR PARKING MECHANISMFiled March 25, 1959 5 Sheets-Sheet 4 ARM/5AM JAM; flu/ m/mem Aprll 14.1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING 0R PARKING MECHANISMFiled March 25, 1959 5 Sheets-Sheet 5 5 4909/5410 JA/Vf! urrmmem UnitedStates Patent 3,128,839 CGNTROL DEVICES FOR HYDRAULICALLY AC- TUATEDEACKHNG R PARKING MECHANISM Archibald James Butter-worth, 7 GroveGardens, Frirnley, near Aldershot, England Filed Mar. 23, 1959, Ser. No.801,254 Claims priority, application Great Britain Mar. 24, 1958 3(Ilaims. (Cl. 1801) This invention relates to a control device forhydraulically actuated jacking or parking mechanism, hereinafterreferred to collectively as jacking mechanism which is carried by avehicle and of the kind in which a hydraulic ram on each side of thevehicle may be brought into circuit by a valve mechanism with a pumpdriven from the vehicle engine so that ground engaging elements of thejacking mechanism may be lowered into contact with the ground therebylifting the road wheels and particularly to such a device in which eachsaid element comprises a roller which may be brought both intoengagement with the ground and to engagement with the wheel of thevehicle so as to be rotated thereby when the vehicle wheel has beenlifted and thus move the vehicle sideways. With such an arrangement itis important that the rams shall not be energised to lower the groundengaging rollers unless the vehicle is stationary or only moving at aslow speed and that the valve should be automatically returned to aposition where the ram is cut olf from communication with the pump whenthe engine stops, rendering it impossible for the jack to be loweredwhen the vehicle is travelling at speed and also preventing the vehiclefrom being unintentionally driven away with the mechanism in its loweredposition.

According to this invention a control device for hydraulically actuatedjacking mechanism of the kind referred to for a vehicle is characterisedin that dentent means are associated with a manually operated valvemechanism for holding the valve mechanism in a position where each ramis cut off from the pump and which detent means are arranged to bereleased only when a control for the speed of the vehicle is in such aposition that the vehicle is stationary or only travelling at low speedand in that means are provided for automatically returning the valvemechanism to a position where the ram is cut off from communication withthe pump when the engine stops.

The control for the vehicle speed may comprise a control lever orselector for a change speed gear box, and which is arranged to releasethe detent when the change speed gear has been adjusted to a first gearposition or neutral position or reverse position.

The detent means may comprise an electromagnetic device in circuit witha source of supply and switch mechanism actuated by the vehicle speedcontrol device.

Means dependent on the pressure in the rams may be arranged to maintainsaid valve mechanism in the position to which it has been brought bymanual control where the ram is in communication with said pump.

The aforesaid means for automatically returning the valve mechanism to aposition where each ram is cut off from communication with the pump maycomprise a spring associated with a moving part of the valve mechanismand which is loaded when the mechanism is moved "ice by hand to bringthe ram into communication with the pump.

The manually operated valve mechanism may comprise a rectilinearlymovable slide valve which at one limit of its movement cuts off the ramfrom communication with the pump and places it in communication with anexhaust or with a fluid reservoir and short circuits the pump, forexample, through said fluid reservoir, and in the other limit of itsmovement places the outlet of the pump in communication with thehydraulic ram.

The slide valve may comprise a plunger located in a cylinder having fouraxially spaced ports, one leading to the exhaust or reservoir andreferred to as an exhaust port, another leading to the pump and referredto as a pump port and a third port between these leading to the ramsreferred to as the ram port and a fourth port leading to the reservoirby a filter which plunger has a first circumferential channel formed init of such a length that at one limit it overlaps the ram port andexhaust port and at the other limit overlaps the ram port and pump portand which plunger has a second circumferential channel formed in it ofsuch a length that at one limit it overlaps the ram port and the fourthport and at the other limit the cylindrical portion separating these twocircumferential channels cuts off the ram port from the fourth port andwhich plunger is provided with a depression or circumferential grooveengageable by said detent when the plunger is in the first of the abovepositions. If the exhausting oil from the rams was carried out byleading it through the same passage as the short-circuited oil from thepump there would be the danger of inadvertent operation of the mechanismdue, for example, to pressure rise caused by a blocked filter. An objectof separating them as set out above is to avoid this danger.

That part of the plunger and that part of the cylinder which aredisposed on the side of the ram port nearer the exhaust port are smallerin diameter than the other part of the plunger and cylinder and whereinthe plunger is movable against the action of a spring in a direction tocut off communication of the ram with the exhaust to a position in whichthe ram is brought into communication with the pump thus when theplunger is brought to this position by hand the differential pressure onthe two parts .of the plunger on opposite sides of the circumferentialhowever, the engine stops the differential pressure ceases to existowing to leakage and the spring will bring the plunger back to aposition in which the ram is brought into communication with the exhaustand it is automatically retained in this position by the detentmechanism which comes into operation as soon as the change speedmechanism is removed from first or reverse positions. The parking devicewill then be Withdrawn to its inoperative position by the action of itsretraction springs.

A hydraulically actuated jacking mechanism for a vehicle having acontrol device as set out above and having a ground engaging roller oneach side of the vehicle which may be brought into engagement with theground and is then driven by a road wheel characterised in each groundengaging roller is mounted to rotate about a fore and aft horizontalaxis and is driven through gearing from a driving roller which is somounted on a part of the jacking -mechanism as to be brought intoengagement with a side of a road wheel rim.

In such an arrangement the driving wheel and gearing are mounted on anarm pivotally attached to a part of the vehicle so as to swing about afore and aft axis and each said ram has a part thereof pivoted to a partof the vehicle so as to swing about a fore and aft aXis spaced inwardlyfrom the first said axis and another part of which ram is pivotallyattached to said arm or a part secured thereto.

The aforesaid gearing may be bevel gearing.

In one construction according to the invention one of said bevelledgears and said driving roller are fixed to a tubular element whichencircles a journal constituting a part of said arm and the other bevelgear and ground engaging roller are mounted on a spindle fixed at rightangles to said arm.

The aforesaid arm may be pivotally mounted on a spring anchorage for oneof the vehicle wheels and the first said part of the ram may be mountedon a wheel axle casing.

The aforesaid ground engaging rollers may be duplicated on each arm andthe duplicated rollers may be fixed to a spindle rotatable in a bearingfixed to said arm and one of said rollers or the spindle has fixed to ita gear wheel which meshes with a gear wheel mounted on said arm anddriven by said driving roller.

The duplicated ground engaging rollers are preferably axially spacedapart on said spindle on either side of a bearing fixed to said arm andthe part of the arm between the rollers comprises a journal portionencircled by a tubular element to which is fixed a bevel wheel whichmeshes with another bevel wheel fixed to one of the rollers and whichtubular element also has fixed to it said driving wheels.

The following is a more detailed description of one embodiment of theinvention reference being made to the accompanying drawings in which:

FIGURE 1 is a longitudinal section through the valve control mechanismand detent mechanism, the associated parts being shown in elevation,

FIGURE 2 is a diagrammatic perspective view of the control mechanism ofFIGURE 1 applied to hydraulic rams arranged to lower rollers intoengagement with the ground and with the road wheels of a vehicle,

FIGURE 3 is a similar view to FIGURE 1 showing the movable valve memberat the opposite limits of its travel,

FIGURE 4 is a side elevation partly in section of one form of rollerengaging mechanism the movement of which can be controlled by the valvemechanism of the present invention,

FIGURE 5 is a section on the line 5-5 of FIGURE 7,

FIGURE 6 is a similar view to FIGURE 5 of an alternative arrangement,

FIGURE 7 is a section on the line 7-7 of FIGURE 4 and FIGURE 8 is asimilar view to FIGURE 5 of an alternative arrangement.

In the arrangement shown in FIGURE 1, the valve mechanism comprises acylinder 10 having four ports 11, 12, 13 and 14 formed therein which areaxially spaced along the cylinder. The port 11 is provided with acoupling 9 for connecting it to a T-piece 8 which communicates with areservoir 7 for fluid and with the inlet 6 of a pump 5. The port 12 isprovided with a coupling 4 for connecting it to the hydraulic rammechanism 60 associated with the combined vehicle jacking and sidewaystraversing mechanism shown in FIGURE 2. The port 13 is provided with acoupling 3 for connecting it with the outlet 2 of the pump 5. The port14 is provided with a coupling 1 for connecting it to one side of afilter 61, the other side of which communicates with the aforesaidreservoir 7. The part of the bore 15 on that side of the port 12 nearerthe port 11 is of smaller diameter than the part of the bore 16 on theother side of the port 12. Located within the bore is a plunger formedwith two circumferential channels 17 and 18 leaving the plunger withthree cylindrical portions 19, 29 and 21. The diameter of the portion 19is such as to be a sliding fit in the part 15 of the bore and is thussmaller than the diameter of the other portions 20 and 21. The axiallengths of the circumferential channels 17 and 18 are such that at onelimit of movement of the plunger (as shown in FIGURE 3) the ram port 12is placed into communica tion with the exhaust port 11 and the pump port13 is placed in communication with the port 14 leading to the filter andoil reservoir. The inlet 6 of the pump is in permanent communicationwith the reservoir 7 so that in this position of the valve the pump isshort circuiting through the oil reservoir and filter. When the plungeris brought to the other limit of its movement as shown in FIGURE 1 theram port 12 is cut off from communication with the exhaust port 11 andbrought into communication with the pump port 13 while the port 14 iscut off from communication with the outlet 2 of the pump. Under theseconditions the ram is energised and lowers the jack mechanism 60 againstthe action of a spring usually provided between the jack plunger and theend of the jack cylinder in the case of a single-acting hydraulic jack.The plunger is retained in the first position described above and shownin FIGURE 3 by an electromagnetically operated detent device comprisinga pin 22 which is engageable with a circumferential groove 23 in thepart 21 of the plunger. The pin is mounted on the armature 24 of asolenoid which is reciprocable in a coil 25 within the casing 62 whichcoil is arranged in circuit with a source of supply and a switch 55 andwhich switch can only be closed by bringing the change speed gear lever56 or selector of a change speed gear box 57 of the vehicle either intolow gear position or reverse gear position. This switch may be of aknown type such as is used, for example, to operate a reversing lamp.Under these conditions the armature 24 is drawn into the coil 25 againstthe action of the spring 26. When so withdrawn the valve may be movedmanually by means of a rod 27 which may protrude through the fire panelof the vehicle and may be fitted with a manipulating knob. The rod isconnected to an extension 29 of the valve by a coupling 28. Theextension 29 projects out through a cover plate 30 at the end of theaforesaid cylinder 10. A spring 31 is disposed between the cover plateand a flange 32 on the plunger. When the plunger is moved to theposition shown in FIGURE 1 against the action of the spring 31 into aposition in which the ram port 12 is brought into communication with thepump port 13, the differential pressure on the annular faces of theparts 19 and 20 of the plunger will retain it in the last mentionedposition against the action of the spring 31 and it will remain in thisposition until pushed back by the driveror until the engine stops andthe pump is no longer driven when it will return to the position shownin FIG- URE 3 of the drawing under the action of the spring when theprojection 22 will again snap back into the groove 23. Leaking of oilalong the plunger into the ends of the cylinder is prevented by twosealing rings 33, 34. It will be noted that when the plunger is at thatlimit of its movement which causes the ram to be actuated as shown inFIGURE 1 and a higher pressure zone exists between ports 12 and 13, i.e.in the annular space 17, such pressure cannot reach these sealing ringsbecause such fluid as leaks past the labyrinth grooves at parts 19 and20 of the plunger, is discharged into ports 11 and 14 which are open toatmospheric pressure. This arrangement prevents the creation of inwardradial pressure against the plunger due to plastic deformation of thetoroidal oil seals, under pressure, 34 and 33 with consequent frictionresistance to manual or spring movement of the plunger.

The difference between the larger and smaller diam eter portions 15 and16 of the cylinder and plunger 19 and 20 are so selected in relation tothe rating of the spring 31 that when differential pressure is set up itis a little less than twice the pressure exerted by the spring so thatwhen pushing the rod 27 in the direction to bring the parts to theposition shown in FIGURE 3 there is about the same resistance tomovement as when moving it in the opposite direction.

As indicated earlier in the specification the invention is particularlyapplicable to an arrangement in which a hydraulic ram is arranged toraise and lower a roller into engagement with the ground, which rolleris driven by a track which is brought into engagement with the side or"the wheel or the wheel rim. Various forms of such an arrangement areshown in United States patent applications Serial Nos. 578,351 (nowPatent No. 2,964,- 118), 667,117 (since abandoned) and 716,945 (nowPatent No. 3,057,424). One form of such an arrangement is shown inFIGURES 4 to 6 Where the plunger 35 of the hydraulic ram is pivotallyconnected at 36 to a mounting 37 for the roller 38. The mounting isprovided with a journal portion 39, the upper end of which has rotatablysecured thereto an extension 40 which is pivoted at 41 to a fixed part42 of the vehicle chassis. The journal portion is encircled by a tubularelement 43 to the lower end of which is fixed a bevel pinion 44 whichengages a bevel wheel 45 constituting a part of the roller frame 46. Theupper end of the tubular element 43 has secured thereto a friction wheel47 which is arranged to be brought into engagement with the wheel rim48. The cylinder part 49 of the ram is pivotally attached at 50 to afixed part of the chassis frame.

The arrangement shown in FIGURES 7 and 8 is similar to that describedabove with the exception that two ground engaging rollers 51, 52 areprovided, fixed to a spindle 53 mounted in a bearing 54 in the part 37which is pivotally connected to the ram. The roller 51 is provided withthe bevel wheel 45 which is engaged by the bevel pinion 44. The journalportion 39 and the extension 40 are separately formed, the splined endof the former engaging a splined socket 63 in the latter.

I claim:

1. A control device for a parking mechanism of a motor-driven vehiclecomprising a hydraulic jack having a cylinder and a piston reciprocabletherein, a groundengaging roller mounted on said piston, a hydraulicpump driven by the vehicle engine for actuating said jack, a valvecasing having port means disposed at spaced intervals therealong, avalve member movable within said valve casing including controllingportions thereon, resiliently yielding means disposed between said valvemember and said valve casing to urge said valve member into a normallyinoperative position, reservoir means for holding a hydraulic fluid,means connecting said reservoir means to said pump and said port means,means connecting said pump to said port means, means connecting saidport means to said jack, said controlling portions when said valvemember is in said inoperative po sition connecting said pump andreservoir means together through said port means and connecting means,manual control means operatively connected to said valve member adaptedto move said valve member into and operative position against the actionof said resiliently yielding means so that said controlling portionsconnect said pump means to said jack through said port means andconnecting means to extend said piston and cause said ground-engagingroller to engage the ground to lift a part of said vehicle therefrom,one of said controlling portions when in said operative position beingacted on by the pressure of the hydraulic fluid to maintain said valvemember in said operative position against the action of said resilientlyyielding means independently of said manual control means and in theabsence of the pressure of the hydraulic fluid the action of theresiliently yielding means moves the valve member into said inoperativeposition, locking means for holding said valve member in the inoperativeposition, power means for releasing said locking means, a change-speedgear box through which the vehicle is driven and having a first gear anda reverse gear, a gear-selecting mechanism mounted in the gear box forselecting the gear to be used therein, and a control device for thepower means actuated by the gear-selecting mechanism when it is moved toa position in which the first gear or reverse gear is engaged and whichcauses the power means to release the locking means.

2. A control device according to claim 1 wherein said locking meanscomprises a spring-biased detent, an electromagnetic mechanism having acoil operatively connected to said detent, said coil being in circuitwith a source of electric supply constituting said power means and witha switch constituting said control device actuated by the selectingmechanism so as to release the detent when the gear-selecting mechanismis brought to a position for engaging first gear or reverse gear.

3. A control device for a parking mechanism of a motor-driven vehiclecomprising a hydraulic jack having a cylinder and a piston reciprocabletherein, a ground-engaging roller mounted on said piston, a hydraulicpump driven by the vehicle engine for actuating said jack, a valvecasing having port means disposed at spaced intervals therealong, avalve member movable Within said valve easing including controllingportions thereon, resiliently yielding means disposed between saidvalvemember and said valve casing to urge said valve member into anormally inoperative position, reservoir means for holding a hydraulicfluid, means connecting said reservoir means to said pump and said portmeans, means connecting said pump to said port means, means connectingsaid port means to said jack, said control-ling portions when said valvemember is in said inoperative position connecting said pump andreservoir means together through said port means and connecting means,manual control means operatively connected to said valve member adaptedto move said valve member into an operative position against the actionof said resiliently yielding means so that said con trolling portionsconnect said pump means to said jack through said port means andconnecting means to extend said piston and cause said ground-engagingroller to engage the ground to lift a part of said vehicle therefrom,one of said controlling portions when in said operative position beingacted on by' the pressure of the hydraulic fluid to maintain said valvemember in said operative position against the action of said resilientlyyielding means independently of said manual control means and in theabsence of the pressure of the hydraulic fluid the action of theresiliently yielding means moves the valve member into said inoperativeposition, the said manually-controlled valve member comprising a plungerand said valve casing comprising a cylinder having four axially spacedports one leading to exhaust, a second leading to the pressure side ofthe pump, a third disposed between the first and second of said portsleading to the hydraulic jack and a fourth leading to said reservoirmeans, said plunger having a first portion of reduced diameter of suchlength so that at one limit of its movement it overlaps the third portand the first port and at the other limit overlaps the third port andthe second port, said plunger having a second portion of reduceddiameter and of such length that rat a first limit of movement of theplunger it overlaps the second port and the fourth port, a cylindricalportion on said plunger separating the two reduced portions to cut ohthe second port from the fourth port at the other limit of movement ofsaid plunger, part of the plunger and part of the cylinder disposed onone side of the third port nearer the first por-t being smaller indiameter than said cylindrical portion but greater in diameter than saidreduced portions, said first reduced portion connecting said cylindricalportion and said part of the plunger in spaced axial relation, and saidplunger being movable against the action of said yielding means in adirection to cut off communication of the jack with the first port to aposition in which the jack is brought into communication with the secondport so that the differential pressure on the confronting faces of saidaxially spaced parts of the plunger maintains the plunger in the latterposition. 5

References Cited in the file of this patent UNITED STATES PATENTSWilliams et a1. Dec. 8, 1925 Williams Nov. 30, 1926 10 (US.corresponding Patent 2,964,118, Dec. 13, 1960)

1. A CONTROL DEVICE FOR A PARKING MECHANISM OF A MOTOR-DRIVEN VEHICLECOMPRISING A HYDRAULIC JACK HAVING A CYLINDER AND A PISTON RECIPROCABLETHEREIN, A GROUNDENGAGING ROLLER MOUNTED ON SAID PISTON, A HYDRAULICPUMP DRIVEN BY THE VEHICLE ENGINE FOR ACTUATING SAID JACK, A VALVECASING HAVING PORT MEANS DISPOSED AT SPACED INTERVALS THEREALONG, AVALVE MEMBER MOVABLE WITHIN SAID VALVE CASING INCLUDING CONTROLLINGPORTIONS THEREON, RESILIENTLY YIELDING MEANS DISPOSED BETWEEN SAID VALVEMEMBER AND SAID VALVE CASING TO URGE SAID VALVE MEMBER INTO A NORMALLYINOPERATIVE POSITION, RESERVOIR MEANS FOR HOLDING A HYDRAULIC FLUID,MEANS CONNECTING SAID RESERVOIR MEANS TO SAID PUMP AND SAID PORT MEANS,MEANS CONNECTING SAID PUMP TO SAID PORT MEANS, MEANS CONNECTING SAIDPORT MEANS TO SAID JACK, SAID CONTROLLING PORTIONS WHEN SAID VALVEMEMBER IS IN SAID INOPERATIVE POSITION CONNECTING SAID PUMP ANDRESERVOIR MEANS TOGETHER THROUGH SAID PORT MEANS AND CONNECTING MEANS,MANUAL CONTROL MEANS OPERATIVELY CONNECTED TO SAID VALVE MEMBER ADAPTEDTO MOVE SAID VALVE MEMBER INTO AND OPERATIVE POSITION AGAINST THE ACTIONOF SAID RESILIENTLY YIELDING MEANS SO THAT SAID CONTROLLING PORTIONSCONNECT SAID PUMP MEANS TO SAID JACK THROUGH SAID PORT MEANS ANDCONNECTING MEANS TO EXTEND SAID PISTON AND CAUSE SAID GROUND-ENGAGINGROLLER TO ENGAGE THE GROUND TO LIFT A PART OF SAID VEHICLE THEREFROM,ONE OF SAID CONTROLLING PORTIONS WHEN IN SAID OPERATIVE POSITION BEINGACTED ON BY THE PRESSURE OF THE HYDRAULIC FLUID TO MAINTAIN SAID VALVEMEMBER IN SAID OPERATIVE POSITION AGAINST THE ACTION OF SAID RESILIENTLYYIELDING MEANS INDEPENDENTLY OF SAID MANUAL CONTROL MEANS AND IN THEABSENCE OF THE PRESSURE OF THE HYDRAULIC FLUID THE ACTION OF THERESILIENTLY YIELDING MEANS MOVES THE VALVE MEMBER INTO SAID INOPERATIVEPOSITION, LOCKING MEANS FOR HOLDING SAID VALVE MEMBER IN THE INOPERATIVEPOSITION, POWER MEANS FOR RELEASING SAID LOCKING MEANS, A CHANGE-SPEEDGEAR BOX THROUGH WHICH THE VEHICLE IS DRIVEN AND HAVING A FIRST GEAR ANDA REVERSE GEAR, A GEAR-SELECTING MECHANISM MOUNTED IN THE GEAR BOX FORSELECTING THE GEAR TO BE USED THEREIN, AND A CONTROL DEVICE FOR THEPOWER MEANS ACTUATED BY THE GEAR-SELECTING MECHANISM WHEN IT IS MOVED TOA POSITION IN WHICH THE FIRST GEAR OR REVERSE GEAR IS ENGAGED AND WHICHCAUSES THE POWER MEANS TO RELEASE THE LOCKING MEANS.